Southern and central Africa
Not Available, Southern and central Africa
Colorless, Greenish, Colorless, Green, gray, Yellow
Green, Black, White, Grey, Green, Black, White, Grey, Green, Black, gray, Black, Green, Black, gray, Black
Irregular/uneven, Uneven
Uneven, UnevenArthur Thomas, Gemstones (2009), Splintery
Ca 2Al 3(SiO 4) 3(OH)Walter Schumann , Gemstones of the world (2001) More from other references
Ca 2(Mg,Fe) 5Si 8O 22(OH) 2Ulrich Henn and Claudio C.